446 SPO Abstracts

662 COMPARISON OF MAGNESIUM AND NIFEDIPINE FOR PRIMARY TOCOLYSIS AND IDIOPATHIC PRETERM LABOR. R.C. FIO~d,X B.N. McLaughlln,X R.W. Martin, W.E. Roberts, .L. WIser,x J.C. Morrison, Dept. Ob/Gyn, Unlv. Mississippi Med. Ctr., Jackson, MS

Objective: To co~are nlfedlplne (N) with magnesium (M) as primary tocolytlc agents for Idiopathic preterm labor (PTL). Patient Population: In this prospective study, 67 patients between 20 and 34 weeks gestation with documented PTL over a 12-month period were randomized to receive 2 mg of oral N q 8 hours versus Intravenous M (sulfate) followed by oral M (gluconate). 2 gm q 4 hours orally. The diagnosis of PTL was established by repetitive contractions usually q 5 minutes with documented cervical change from a previous exam or cervix> 2 cmf> 50% effaced. Multiple gestation, chorlomanlonltlS, rupture of the membranes, fetal distress, growth retardation, or allergy to M or N were exclusion factors. Main Outcome Measured: Pregnancy prolongation Index (days prolongation from diagnosis of PTLlldeal prolongation [to 37 weeks] from PTL), number delivering < 37 weeks, birth weight, maternal complications for tocolytlcs and duration to delivery after treatment. Results: There was no difference In the number of panentS delivering < 37 weeks, the duration of treatment, Interval to delivery, PPI, PTB, or BW.

Treatment Interval * BW*

Group Number (weeks) PPI* PTB* (gm)

M 29 7.0 + 5.2 0.96 + 0.55 11 2565 + 763 N 39 5.7 + 3.9 0.97 I 0.59 13 2768 I 662

*not s I Tn' fl cant -conclus ons: The results of this study shOw that N Is a useful agent as a first-line tocolytlc with an effectiveness comparable to that of M. No evidence of fetal or neonatal compromise was noted and there was no statistically significant difference between pregnancy prolongation or preterm births.

663 UMBILICAL BLOOD SAMPLING. IS IT IMPORTANT WHERE TO

SAMPLE? B. Peskinx. N Lazebnjk, J. Blanksteinx. Dept. Ob/Gyn. Case Western Reserve Univereity. MI. Sinai Mad Ctr, Cleveland. OH.

Umbilical cord blood sampling at birth greatly enhances a889eement of the newborn's respiratory status. This study was conducted in order to address two questions. 1) Does the cord blood gas result depsnd on the cord segment sampled? 2) Does fetal distreee play any roll in choosing the cord segment to be studied? Three groups of patients were studied with 10 patients in each group. Group I Elective cesarean section with apgar score 01 > 9 at 1 and 5 minutes. Group II Normal spontaneous vaginal deliveries with no evidence of fstal streee as shown by fstal heart tracings and apgar score of > 7 at 1 and 5 minutes. Grou'l III newborns delivered by forceps / vacuum extrac10r I cesarean section due to abnormal fetal heart tracings and scalp pH sample of < 7.20. For each group the cord was clamped immediately in 3 different sites. Near the placenta, mid portion and about 5 em from the newborn. Blood gas samples within sites in the same newborn and between the 3 groups were compared by analysis of variance (ANOVA). The 3 groups were statistically different in cord artery pH results regardless 01 the site sampled (7.27+ 0.049 vs 7.26 + 0.033 vs 7.17 + 0.06 p< O.OOt for groups I, II , and III respectively). In groups I and II where no letal distreee was present no difference was found in cord artery pH between the different sampling sites. However in group III where biochemical evidence 01 fetal distreee was present a significant difference was found in the arterial pH between the three sites sampled. In the site closer to the newborn the mean pH was 7.17 + 0.06, in the mid sec1ion of the cord the pH was 7.18 + 0.067 and in the site near the placenta the cord pH was 7.21+ 0.079. The same was found when the pC02 was studied. Analysis of the the cord vein blood gases showed significant differences between groups but no difference within groups. In conclusion. the site sampled may playa roll in documenting the respiratory status if acidosis is present.

January 1992 Am J Obstet Gynecol

664 CLINICAL APPLICATION Of THE KLEIHAUER-BETKE TEST. A.R. ~ucre,x J.N. Martin, Jr., R.C. Floyd,X P.G. Blake,X IT.'r. o erts, J.C. Morrison, Dept. Ob/Gyn, Unlv. Mississippi

Med. Ctr., Jackson, MS Objective: Determine the accuracy of quantltatlon of

fetomaternal hemorrhage by Klelhauer-Betke (KB) testing to predict the maternal/neonatal outcome. Population: All women> 20 weeks' gestation at risk for feromaternal hemorrhage (abdominal trauma, cocaine Ingestion, placenta previa, and abruptio placenta) were consecutively evaluated In the labor and delivery suite. A case series study design was utilized. The analysis of maternal whol e blood for the presence of fetal cell s was acco~ll shed by the KB procedure using a commercially available kit (Sure-Tech Diagnostics, Inc.). If positive, It was repeated at 6-hour Intervals (If the patient remained undelivered) for 24 hours. Main Outcome Measured: The presence or absence of abruptloi'i at delivery, the estimated gestational age, as well as neonatal hematocrit, weight, pH, and Apgar score were assessed In women who had positive and negative KB tests. Results: Seventy-six patients were enrolled during the stiJdYjieriod and a total of 109 KB tests were performed.

AbdOminal placenta Substance suspected Trauma Previa Abuse Abruption

N 37 8 15 16 + KB 4 2 5 7 + Abruptlon 0 1 1 5 NN Hct < 45 0 0 0 1 The presence of a posltl ve RB test was not of assl stance In Identifying significant fetomaternal hemorrhage. Neonatal (NN) outcome was good. There was no correlation between the KB tests either Initially or on serial examination with Apgar scores or cord blood pH. Of the 18 patients with positive KB tests, only 1 Infant had a hematocrit of < 45%. Even when positive, the amount of estimated fetomaternal bleeding by KB testing did not correlate with any outcome parameter. Conclusion: Significant fetomaternal bleeding or neonatal morbidity Is not predicted by a positive KB test.